1. Field of the Invention
This invention relates to a rubber-modified polystyrene resin composition, more particularly to a rubber-modified polystyrene resin composition for making an electroplatable article that has superior electroplating property while preferably maintaining satisfactory physical properties.
2. Description of the Related Art
Rubber-modified polystyrene resin compositions have been widely used for producing several products, such as interior and exterior parts for automobiles, parts for electric and electronic equipments, or the like because of good processability and mechanical strength thereof. Specifically, the mouldings made of acrylonitrile-butadiene-styrene (ABS) resin are usually electroplated to impose a metallic appearance to the mouldings, such as the parts for automobiles.
Before being electroplated, the mouldings made of ABS resin are acid-etched so as to provide the mouldings with micro-structures (such as micro-recesses) on the surface thereof. The adhesion of the formed metallic electroplating layer with the surface of the mouldings can be enhanced thereby.
However, there are the following problems when the mouldings made of conventional ABS resin are electroplated:
(1) There are pinholes formed on the surface of the electroplated mouldings so that the appearance of the electroplated mouldings is not satisfactory.
(2) The etching property of the mouldings made of the conventional ABS resin is inferior so that the adhesion of the electroplating layer to the surface of the mouldings is insufficient and thus the electroplating layer peels easily.
(3) The mechanical strength of the mouldings made of the conventional ABS resin is reduced after etching and electroplating so that the application of the mouldings is limited.
Taiwanese Patent No. TW322488 discloses a rubber-modified styrene resin composition which has superior impact strength, gloss uniformity, and thermal stability. However, the problems regarding the pinholes and the inferior adhesion of the electroplating layer still exist when an article made of the rubber-modified styrene resin composition is electroplated.